Author Topic: Color changes when photos are zoomed  (Read 20298 times)

Offline HvTFoto

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Color changes when photos are zoomed
« on: August 13, 2012, 01:12:51 PM »
I'm running PM 5 on MacPro running Mountain Lion. I have a calibrated monitor (SpectraView 27"). When I zoom the colour shifts (paler/less vivid in zoomed in mode). I experience the same in PM 4.6.9. It doesn't matter if the file is net or jpg (unedited). Colour management is turned on (profile if undetermined: ProPhoto). Is this behaviour normal or am I missing out something in my settings (I shot raw with Nikon DSLR, colour space Adobe RGB).

//Hans
« Last Edit: August 13, 2012, 01:14:39 PM by HvTFoto »

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #1 on: August 13, 2012, 03:48:13 PM »
Hans,

I have not seen that behavior before.  Can you take screenshots of both zoomed and unzoomed images?

Use the 'Attachments and other options' link when you're composing your reply to this message and there you'll be able to upload your JPEG format screenshot.

Thanks,

-Kirk

Offline HvTFoto

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Re: Color changes when photos are zoomed
« Reply #2 on: August 13, 2012, 09:34:49 PM »
Kirk,

Here we go. First picture is normal view, second pictures zoomed in.

//Hans



[attachment deleted by admin]

Offline HvTFoto

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Re: Color changes when photos are zoomed
« Reply #3 on: August 13, 2012, 11:29:19 PM »
Thanks for the speedy reply. I guess Adobe has as I don't see any difference between scaled down and zoomed in images in CS 6.

//Hans

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #4 on: August 13, 2012, 11:48:31 PM »
Hans,

Thanks for the speedy reply. I guess Adobe has as I don't see any difference between scaled down and zoomed in images in CS 6.

Well, that was just my hunch/estimate as to what is likely going on.  Can I have your sample image for further research?  Send me a personal message (the forum software calls it a 'PM') and I'll arrange for a place you can upload the image.

Thanks,

-Kirk

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #5 on: August 15, 2012, 07:52:10 AM »
Hans,

Thanks for the sample image.  On my system the image doesn't become less saturated in color when zoomed in.  It looks very much similar to the scaled-to-fit image.

After discussing the issue with another member of the team (and getting some sleep as well) we have determined that color cast changes should indeed be nearly undetectable.

I think perhaps PM ran out of memory while trying to perform color management on that image in 100% size and was forced to use the non-color managed version.  I can add some logging code to the color management to put out messages when color managed bitmaps can't be generated.  We could then look in your log file and see if that is the case.

Let me know if you're interested.

-Kirk

Offline TGeist

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Re: Color changes when photos are zoomed
« Reply #6 on: August 17, 2012, 06:53:39 PM »
I slowly get the uneasy feeling that there's more weird things going on than we might think.

I am running OS X 10.8 on a NEC PA271 with either Spectraview II or Multi Profiler (doesn't make a difference).
PM Color Management is set to sRGB and Color manage thumbnails and previews. RAW rendering is OFF.

When PM first goes through Nikon NEFs (D300 and D700) and Canon CR2 (5D Mark II) in the Contact Sheet it briefly shows a black bar on top and bottom of the thumbnails. Reds seem very saturated. The bars disappear and the images show up in a more greenish tint. If I turn off the color management icon in the Contact Sheet, the images show a more reddish version again. This happens in blocks. A whole bunch of images blink the first time I toggle the CMM icon and then show the tint difference, some rows further down they never blink and there's no difference visible.

When I go to Preview, the images look ok with the slight reddish tint. If I zoom in they are less saturated in the reds.

First attachment is Contact Sheet, CMM on.
Second is Contact Sheet CMM off.
Third is Preview (CMM on/off doesn't matter)
Fourth is Preview zoomed in.

[attachment deleted by admin]

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #7 on: August 17, 2012, 08:29:03 PM »
I slowly get the uneasy feeling that there's more weird things going on than we might think.

I am running OS X 10.8 on a NEC PA271 with either Spectraview II or Multi Profiler (doesn't make a difference).
PM Color Management is set to sRGB and Color manage thumbnails and previews. RAW rendering is OFF.

When PM first goes through Nikon NEFs (D300 and D700) and Canon CR2 (5D Mark II) in the Contact Sheet it briefly shows a black bar on top and bottom of the thumbnails. Reds seem very saturated. The bars disappear and the images show up in a more greenish tint. If I turn off the color management icon in the Contact Sheet, the images show a more reddish version again. This happens in blocks. A whole bunch of images blink the first time I toggle the CMM icon and then show the tint difference, some rows further down they never blink and there's no difference visible.

I can only speak to the part about the initial thumbnails.  The thumbnails with the black bars are the EXIF thumbnails and are of very low quality, but they load really fast so PM uses them temporarily while higher quality thumbnails are loaded.

When you toggle the color management off/on, PM has to generate new thumbnails color managed (or not if you've turned it off) and this process does take some time to complete--it isn't instantaneous.

As for assigning sRGB in the Color Management settings, that profile is only used when the image being rendered has no color profile assigned to it (or embedded into it).  What color mode do you shoot in on your cameras?  It is likely that you have Adobe RGB as a setting which is a much larger gamut color space.

How do your images look in Photoshop?

-Kirk

Offline TGeist

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Re: Color changes when photos are zoomed
« Reply #8 on: August 18, 2012, 05:22:48 AM »
The part with the EXIF preview was kind of clear to me.

What puzzles me is the fact that toggling the CMM switch in Contact Sheet view shows a difference only for some of the thumbnails: PM shows 5 rows of thumbnails on my screen. Toggling will switch 2 or 3 rows (not always exactly full rows though). The other thumbnails do not change in color. When I scroll further down, some other 1, 2 or 3 rows change in color while the others stay unaffected. Happens with NEF, CRE2, JPEG ...

Changing the thumbnail size does change which ones are affected.

All the cameras are set to sRGB.

The colors in Photoshop look like what Preview shows. The thumbnails in Contact Sheet seem to either over or under saturate colors (mostly reds) IF they toggle. If they don't they seem to be like what Preview shows.

When I zoom to 100% in Preview mode for the first time I can see the colors as they were in the non-zomed version for a second. Then the color fades out.

I actually get the ugly feeling that Mountain Lion might be messing around here. We have another computer running with an NEC 2690, also calibrated with Spectraview II and it seems to have a green cast since ML is on.

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #9 on: August 18, 2012, 06:25:51 AM »
The part with the EXIF preview was kind of clear to me.

What puzzles me is the fact that toggling the CMM switch in Contact Sheet view shows a difference only for some of the thumbnails: PM shows 5 rows of thumbnails on my screen. Toggling will switch 2 or 3 rows (not always exactly full rows though). The other thumbnails do not change in color. When I scroll further down, some other 1, 2 or 3 rows change in color while the others stay unaffected. Happens with NEF, CRE2, JPEG ...

Changing the thumbnail size does change which ones are affected.

All the cameras are set to sRGB.

The colors in Photoshop look like what Preview shows. The thumbnails in Contact Sheet seem to either over or under saturate colors (mostly reds) IF they toggle. If they don't they seem to be like what Preview shows.

When I zoom to 100% in Preview mode for the first time I can see the colors as they were in the non-zomed version for a second. Then the color fades out.

I actually get the ugly feeling that Mountain Lion might be messing around here. We have another computer running with an NEC 2690, also calibrated with Spectraview II and it seems to have a green cast since ML is on.

OK, then we're going to have to do some investigation.  Have you re-calibrated your monitors with your Spectraview II colorimeter since your transition to Mac OS X 10.8?

I'll add some logging code to the color management routines and with your help we'll be able to get to the bottom of the issue.

-Kirk

Offline TGeist

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Re: Color changes when photos are zoomed
« Reply #10 on: August 18, 2012, 06:32:24 AM »
Yes, it's been re-calibrated. In the meantime however I switched to NEC Multi Profiler (which shows identical results).

(Multi Profiler is NEC's newer concept of factory calibrating monitors and then tracking the monitor throughout its use.)

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #11 on: August 18, 2012, 06:37:22 AM »
If you use the built-in Preview application, how do your images look?

-Kirk

Offline TGeist

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Re: Color changes when photos are zoomed
« Reply #12 on: August 18, 2012, 07:00:32 AM »
OS X Preview shows the images like they look in Photoshop (CS6), in Photo Mechanic's Contact Sheet with CMM off and in PM's Preview.

PM's Preview zoomed 100% looks like thumbnails in Contact Sheet with CMM on. (less saturated colors, mostly reds).

PM's Preview thumbnails depend on the CMM setting Contact Sheet was in before Preview was started.
If CMM there was off, Preview's thumbnails look hyper-saturated (like the EXIF previews?). Just like OS X Preview's thumbnails do (!!).
If PM's Contact Sheet CMM gets switched, PM Preview thumbnails don't change until "Show all/selected Thumbnails" in Preview gets switched.

Adobe Bridge is constant. It shows colors exactly like Photoshop does, for thumbnails and previews.


P.S.: Thank you for all your efforts!!!

Offline Kirk Baker

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Re: Color changes when photos are zoomed
« Reply #13 on: August 18, 2012, 07:13:51 AM »
OS X Preview shows the images like they look in Photoshop (CS6), in Photo Mechanic's Contact Sheet with CMM off and in PM's Preview.

PM's Preview zoomed 100% looks like thumbnails in Contact Sheet with CMM on. (less saturated colors, mostly reds).

PM's Preview thumbnails depend on the CMM setting Contact Sheet was in before Preview was started.
If CMM there was off, Preview's thumbnails look hyper-saturated (like the EXIF previews?). Just like OS X Preview's thumbnails do (!!).
If PM's Contact Sheet CMM gets switched, PM Preview thumbnails don't change until "Show all/selected Thumbnails" in Preview gets switched.

The thumbnail gallery uses the color management setting from the contact sheet toolbar.  Changing the setting back in the Contact Sheet window doesn't cause the thumbnails to spontaneously redraw.  Scrolling should cause them to update though (as long as the currently visible ones can be scrolled completely out of view and back again.)

Are you willing to run a logging version of PM5?

In a couple of hours I will be gone for most of the day and evening, but I could probably get something out to you tomorrow morning.

-Kirk

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Re: Color changes when photos are zoomed
« Reply #14 on: August 18, 2012, 07:22:21 AM »
Yes, no problem, I'd run a logging version.

I will be out of town (and without computer - yay!) from tomorrow until Wednesday, so there's no hurry.
If I make further discoveries or observations, I'll let you know.